Posted
by
pudge
on Wednesday January 28, 2004 @01:45PM
from the bring-it-on dept.

tackaberry writes "Apple has released an update for AirPort. Version 3.3 (AEBS firmware version 5.3) includes support for Wi-Fi Protected Access (WPA) specification for non-Extreme AirPort cards (WPA was added for Extreme cards last fall in version 3.2), an alternative to the oft-maligned Wired Equivalent Privacy (WEP). Those who wish to use WPA will have to have Mac OS X Panther 10.3."

Many cryptographers are confident that Wi-Fi Protected Access addresses all the known attacks on WEP. It also adds strong user authentication, which as absent in WEP.

Ok, user authentication is good, but what are the "known attacks on WEP"? I'm using a Linksys access point which obviously can't be upgraded to WPA with this update, so should I be concerned that my 128-bit WEP key isn't good enough?

You should be quite concerned. WEP is poorly implemented cryptography, you should see what LinkSys supports to limit access to your Router by MAC address, this won't solve the problem of your data not being 100% unreadable and such when sent over your connection, but at least no one else could hop on your network easily and steal bandwidth.

Some implementations of WEP are weaker than others. The main problem is that given enough data from your network I can break your key rather quickly. Usually you are looking at several GBs of data (3 to 5GB usually). While someone wardriving wouldn't bother a neighbor with nothing but time might.

If you have a Mac...and I'm assuming you do...go check out the Kismac tool.

WPA also has some weaknesses...mainly in the WPA-PSK (pre-shared key) implementation that most home users use. You can do a dictionary attack against the key.

Not only is there a WPA PSK dictionary attack, it is actually an OFFline dictionary attack - meaning that the attacker can sniff a valid authentication, then take the sniffed data back home and run the dictionary attack on his own without involving the real gatekeeper (who otherwise would see n invalid attempts in a row and have a chance to raise an alarm).

In general, any scheme where you send a random number to the client, he takes that and adds the secret sauce and sends it back for your comparison is vulnerable to offline dictionary attack.

The good news is that you can pretty easily trash an offline dictionary attempt by making up a really long and obscure passphrase.

is bounded by the entropy of the key. If you use a weak key, it will be vulnerable. This is not a legitimate criticism of the protocol.

If you are worried about someone accessing your network, then you have to assume the attacker is active (can insert messages and attempt to authenticate), so eliminating offline attacks doesn't buy you much. AFAIK, this is the case with all authentication protocols.

I'm not sure I agree. If the only attack available is an online dictionary attack, then the bar is significantly lowered if the service does the right things. It can rate limit to raise the cost, it can lock an account after small-n bad passwords are given, it can raise an alarm that can identify (at least to some extent) the intruder... All of these mitigations are useless if an offline attack is possible.

Sure, but you are making the protocol too dependent on the rest of the system, and the behavior of the rest of the system will change.

Have you ever tried to design a server with account lockouts for incorrect password entries? Think DOS.

Can you give me an example of a single authentication protocol which is secure against weak passwords? I will let you use whatever mitigation metric of your choice, provided that you let me stipulate that it be production code, which must support a massive number of simul

Security is a holistic thing. The weakest link and all that. It's not that I'm making the protocol 'dependent on the rest of the system,' it's that I'm having each piece of the system do its job.

I'm not suggesting that 'a' and 'b' will be a strong pair in the circumstances, merely that '9d42f3054f4bed06e0f9a982ccaaf383' won't be necessary to the extent that it is in the face of offline attacks. That is, that the amount of entropy you need to be secure goes down substantially when you are resistant to offli

No my point is that because it's a system. the weakest link will be the password. Attempts to strengthen the system so that a weak password is not exploitable are bound to fail and end up covering only a few avenues of attack.

In a mutual authentication system, the client is protected from a dummy server as well. If you do not think this is important, then you don't care about all of the attacks to spoof websites (paypal). I do care about these attacks and don't consider a protocol in which I pass a passwor

the keys used in WEP are static, not dynamic . sure, 128-bit RC4 is generally secure, but it would be really secure if the key was rotated by the access point . this is done by WPA . WPA is only a placeholder until WPA2 is released, featuring wireless robust authentication protocol and cipher block chaining message authentication code protocol or CCMP.

Have you checked to see if Linksys has a firmware update available that adds WPA support for your access point? My Netgear WGR614 didn't support WPA until a week or so ago, although the firmware that's available is still in beta. BTW, so far it works pretty well with my 12" PowerBook G4 and iBook SE/466.

In a word, YES. WEP is a horribly insecure protocol. All it takes is time, and you can sniff WEP keys out of the air. My basic strategy for securing WiFi is to place the access point outside of my firewall, and use some VPN (or a simple ssh tunnel) to access my "real" network.

The moral: never rely on WEP to secure your network, always use some higher-level encryption to secure sensitive information.

I don't know which Linksys product you are using, but I'm using a WRT54G. When I first bought the router it only supported WEP, but then a firmware upgrade came one day that had WPA support. Check Linksys support site.

My iBook G4 running Panther connects to my router just fine using WPA Personal (Pre-shared key in Linksys). Although I've been thinking of playing around with WPA Enterprise (RADIUS), but that takes time:)

Here's a short excerpt from Niels Ferguson and Bruce Schneier's excellent book Practical Crypography:

The standard (WEP) was designed by a committee which didn't include any cryptographers. The results where horrible....RC4 is a stream cipher and needs a unique nonce. WEP didn't allocate enough bits for the nonce, with the result that the same nonce value had to be reused, which in turn resulted in many packets being encrypted with the same key stream. That defeated the encryption properties of the RC4 str

It's about time they put support for Windows product activation on their Airport. Just think of all those poor Windows users whose machines suddenly refuse to work because they were never allowed to activate through their wireless Net connections...

It's nice that apple is updating their WPA security for the airport, but it's still hard to get on Cisco secure access points.
The place i work at has a Cisco Aironet 1100 and they have it set up to use WPA. I've tried many times to figure out how to get on it but I haven't found anything that works. The system admin couldn't help me either.
I wish apple would step up and support enterprise level wireless hardware.

... and it ought to be possble. WPA was designed to be implementable with a firmware upgrade to existing 802.11b hardware. See here [tidbits.com] for more on that - scroll down about halfway on the page.

I have a perfectly useable 500 MHz G3 iBook that's going to be cut off from my company's wireless when they move to WPA, because it's not AirPort Extreme capable. Is Apple's response going to be "go buy a new laptop - your less-than-two-years-old machine is obsolete"? Even though it's supported by Panther (which impr

They're talking about base stations here, not the wireless cards. The regular AirPort cards are upgraded, as I can confirm on my 466Mhz iBook SE. It just doesn't upgrade non-Extreme base stations. The Graphite one especially cannot handle this with it's sad little 486. =\

Is it possible to have both WPA and WEP on the same wirless network? I have a windows 2000 machine which doesn't support WPA, so I'd like to use WEP for it while still using WPA for my Mac. My SMC base station allows to setup the network like this, but my Mac just quits working ("Error connecting to Network" alert).

One solution to this is to connect your win2K machine to your network via wired ethernet. That takes your rate limiting machine off your wireless network. Since it's wired you don't have to bother with either WEP or WPA for that machine.

That's the same thing I did with my iMac w/ AirPort (not Extreme) card. I wanted to go pure-g, rather than mixed-b/g. Added a switch to my AEBS, and used the built-in ethernet rather than the 802.11b for the iMac.Either move your router near the machine, or get a long

I'm quite happy with WPA-PSK (with the caveat that you need to pick a very strong passphrase to avoid offline dictionary attacks). My wife has an iBook G4 and I have a TiBook with a Linksys WPC54G in it and they all talk to a Linksys WAP54G. It was all miraculously easy.

Then I had to get a couple of Windows laptops to work. That was misery!

First, you must be running XP. I guess that's fair, since Apple says you must be running Panther.

Next, you have to have a wireless card that has drivers updated with WPA support. Irritatingly enough, a WPC54G with the latest drivers will work, but a WPC55G (A+G card) won't because the drivers aren't updated. Grr!

I did finally get it to go, but it was a whole lot easier on the Mac.

I also wanted to set up WPA "Enterprise" with an eye towards deploying that at the office. I still haven't figured out how to get that to work, unfortunately. But the PSK variety was surprisingly easy.

Yes, I know. But it's not just any RADIUS server, it has to be able to participate in the WPA stuff. I believe FreeRadius is the only open-source one that will do it, but configuring it all seems very, very painful.

Just installed the 1.2.8 firmware for my DLink DI624 (b) and turned it on. It works great! Bit weirded out by one thing, though: Apple's system profiler lists the AirPort card's firmware as 3.3b1. Bad Apple!

I installed this about the same time I upgraded to DSL. Now my 5.8GHz Uniden phone is fuzzy. Filters aren't working. I know it's the phone's fault, but convincing the techs at Uniden that it's not Airport's fault is difficult. So, anybody else having this problem before or after installing this update? Also, anybody know how to fix it? Dang! I spent a lot of money on that phone system for it to not work with DSL. My cheap $10 phone works just fine... (0_0)